When I first began cooking, I thought cooking oil was cooking oil. I had one type - the giant yellow bottle of vegetable oil and I used it for everything. As I became more experienced in the kitchen and more aware of what was in the products I was eating and serving my family, I realized that not all oils are the same.
There are four basic different types of oils that we use in cooking. Monounasaurated fats are fats like olive oil or canola oil. Polyunsaturated fats are oils like sunflower or soybean oil. Saturated fats are commonly butter, coconut, or palm oil. Trans-fats are hydrogenated fats used in things like fast food French fries.
Monounsaturated fats are the best types of oils for your heart. The best type of olive oil to use is extra virgin because it is the least processed of the olive oils. Olive oil is idea for cooking things over medium heat or for stir frying meats or vegetables. It also works well for vinaigrette and salad dressings. Canola oil has been genetically modified and processed. It has a higher smoking point than olive oil and is used by some for cooking over high heat.
Polyunsaturated fats include things like corn, safflower, sunflower, soybean, and peanut oil. They should not be cooked with because they are unstable when exposed to heat and light. Some studies show they should be avoided because they cause free radicals which are bad for your body.
Saturated fats are found in animal fats and tropical oils like coconut. They are very stable even at high heat which is why they are ideal for baking or deep frying. They will not oxidize under high heat like other fats.
Trans fats or hydrogenated fats should be avoided. They include things like margarine and the oil that fast food restaurants use. They are linked to heart disease and cancer.
Like anything else, when choosing an oil, you should look for the purest and least processed oil available. Also be aware that oils like corn, canola, and cotton seed run the risk of being genetically modified. Chose with care.